Here was the hub of a business that raked in $10 million over 15 years, prosecutors said.

Sure, it was just one bedroom, and terribly cramped — what do you expect for $600-a-month, rent-stabilized?

But once through the door to 2F — an apartment Gristina rented for six years — johns starred in their own, uncut, XXX version of Lifestyles of the Rich and Amorous, as The Post can now reveal.

Beckoned into the teeny living room — perhaps by one of the joint’s alleged $2,000-per-visit lovelies — corporate honchos can leave their corner-office swivel chairs behind and get frisky on the wrought-iron, pillow-festooned day bed.

You’ll be treated like royalty: Among the chaos of maroon and crimson pillows is one sporting a Ralph Lauren crest, complete with a gold embroidered “RL” monogram and crown.

And who needs 900-count linen when synthetic paisley fabrics are so much more washable?

Enjoy the scent of vanilla cinnamon candles — yum! — and the dizzying, competing scent of incense. If that doesn’t inspire swooning, just hit play on Christina Aguilera’s album “Stripped,” already cued up as the sexy-time soundtrack in the living room’s CD player. But pay no attention to the plastic Buddha staring at you from the mantel of the working fireplace.

Are you a captain of industry distracted from love by less amorous appetites? Swagger into the capacious galley kitchen, roomy enough for one person, where select delectables lay in the cupboards. Fancy a little petit dejeuner? A box of Fruity Pebbles is at your fingertips. The soup du jour? Progresso. There’s even a microwave for the hungry john with no time for simmering — when it’s not being allegedly used as a cash safe box.

But better take it black — who knows how long that milk’s been sitting there next to the Coors.

It’s been a couple weeks since Gristina has been stuck in Rikers Island in lieu of $2 million bail. And there’s been no housekeeping help from Gristina’s alleged fellow madam, strawberry-blond stunner Jaynie Baker — who sources say also has been indicted for promoting prostitution and who remains on the lam.

Finally, the boudoir — let’s just say it’s not the presidential suite at the Waldorf.

Most of Gristina’s alleged business was out-call, according to sources familiar with the operation. But for those top-dog johns with cathouse tastes, a queen-sized bed sits in a frame just inches off the floor. Wealthy johns who haven’t slept on the floor since their dorm room at Harvard Business School will love it.

Inside the closet? A spaghetti-strapped red cocktail dress and a silver one dangle from hangers. The top shelf is a muddle of bundled-up frumpy sweaters and hoodies, perfect for the walk of shame home.

There are two red-shaded lamps on end tables to either side of the bed. A tiny, 15-inch TV — circa 1997 — sits on a tiny white dresser.

Speaking of which, let’s peek in the three drawers.

The bottom one is packed with DVDs. “Casablanca.” “The Seven Year Itch.” “Sex and the City” — not exactly a male aphrodisiac. And Harry Potter?

Jackpot! In the top drawer, the drug store nookie-aisle mother lode. CVS-brand and K-Y lubricants. Trojan ENZ condoms. And for clients who need to think of baseball? There’s an aid for that too — an actual hardball.

Oh, one last thing. There’s another Buddha, this one just a head without a body, staring at the bed from a set of shelves directly across the tiny room. Pay no attention to him, either. He might just be bugged.